Helena Petrovna Blavatsky. This tendency to use abbreviations for theosophists started in her day. She actually wrote in her own copy of 'The Voice of the Silence' "From HPB to H.P. Blavatsky, with no kind regards". This is usually interpreted to mean that the inner HPB - the higher self - didn't appreciate the troubles her personality - H.P.Blavatsky - got herself into.